Health / Medical Topics |
D Vitamin
Definition 1
A family of lipo-soluble steroids important to the absorption, metabolism, and function of calcium and phosphorus and the growth and development of bone and tooth enamel. Found naturally in animal tissues, cholecalciferol (vitamin D3) is formed in the skin when ultraviolet light activates cholesterol conversion into vitamin D3. Ultraviolet irradiation of ergosterol (plant vitamin D) forms ergocalciferol (vitamin D2). (NCI Thesaurus)
Definition 2
A class of fat-soluble vitamins that are seco-sterol precursors to the active hormone, 1,25-dihydroxy vitamin D. (NCI Thesaurus/CRCH)
Definition 3
A nutrient that the body needs in small amounts to function and stay healthy. Vitamin D helps the body use calcium and phosphorus to make strong bones and teeth. It is fat-soluble (can dissolve in fats and oils) and is found in fatty fish, egg yolks, and dairy products. Skin exposed to sunshine can also make vitamin D. Not enough vitamin D can cause a bone disease called rickets. It is being studied in the prevention and treatment of some types of cancer. (NCI Dictionary)